<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>BFC</title>
    <style>
        .aside {
            float: left;
            width: 200px;
            height: 300px;
            background-color: aqua;
            color: #fff;
        }
        .container {
            width: 500px;
            height: 400px;
            background-color: blueviolet;
            /* 解决方法 */
            overflow: hidden;
        }
    </style>
</head>

<body>
    <div class="boxContain">
        <div class="aside">善诚大佬</div>
        <div class="container">cscdl</div>

    </div>
</body>

</html>